The present invention relates to a text transfer device of a fascimile, and more particularly to a transmit text transfer device which is able to perform one hundred percent complete reproduction of a text and error-free feeding of sheet of text.
In a composition of a conventional transmit text transfer device, as shown in FIGS. 1 and 2, reduction gears 3 are engaged with both sides of a gear 2 of a motor 1 that generates driving force, the two reduction gears 3 are engaged with a main gear 4 of a main roller 5 and a feed gear 4A, of a feed roller 7. The main gear 4 has a total of Z.sub.M gear teeth and the feed gear 4A has a total of Z.sub.F gear teeth. A pinch roller 8 is in close contact with circumference of the feed roller 7, and a separating rubber plate 6 is in close contact with circumference of the main roller 5.
In conventional composition, for the main roller 5, a main roller shaft 13 is inserted into a center hole that goes through from one end to the other end of the main roller 5, in such a way that an inner slide 12, into which a fixing pin 11 is inserted, is inserted as well in order to fix the axis of the main roller 5, and as shown in FIG. 3, an outer slide 10, which is formed with an angle of .theta., is inserted into on the outer surface of the inner slide 12. And at both ends of the main roller shaft 13, as shown in FIGS. 1 and 2, the axis of the main gear 4 is fixed having a one-way bearing 14 inserted therein, in order to cut or transfer driving force to the main roller 5.
In the conventional transmit text transfer device as shown above, when linear velocities of the main roller 5 and the feed roller 7 are represented by V.sub.M and V.sub.F, respectively, and relationship between V.sub.M and V.sub.F is V.sub.M =V.sub.F or V.sub.M &lt;V.sub.F, the imbalance between the two velocities can be corrected either by adjusting diameters of the main roller 5 and the feed roller 7 to be the same on the one hand and velocity reduction ratio of engaged gears to have a ratio of Z.sub.M &lt;Z.sub.F on the other hand, or by controlling velocity reduction ratio of the engaged gears to have a ratio of Z.sub.F =Z.sub.M on the one hand and ratio of diameters of the main roller 5 and the feed roller 7 to have a ratio of D.sub.M &lt;D.sub.F on the other hand. However, the latter is more often used in conventional transmit text transfer device, therefore, when sheet of text is bitten by the main roller 5, the main roller 5 is run idle by one-way bearing 14 that is engaged with the main gear 4, in order that transmit sheet of text is transferred by linear velocity of the feed roller.
In maintaining an interval between one transmit sheet of text and the next, linear velocity difference is generated between the main roller 5 and the feed roller 7 while one sheet of text is completely fed and the next sheet of text is ready to be fed, and the linear velocity difference lets the one-way bearing 14 run the main roller 5 by the degree of .theta. as shown in FIG. 3B, thereby, when the next sheet of text is bitten by the main roller 5, the main roller 5 runs idle by the degree of .theta. even though the main gear 4A transfers driving force to the main roller 5, resulting in that the interval as far as circumferential distance of the .theta. is generated between one sheet of text and the next sheet of text.
Thereby, the conventional transmit text transfer device has a setback that at the time before a sheet of text is bitten by the feed roller 7 at a reading position 9 with the sheet of text bitten by the main roller 5, i.e., at the time when the sheet of text is fed as far as a distance A as shown in FIG. 4A, the sheet of text is affected by the linear velocity of the main roller 5, thereby, transfer distance of the sheet of text becomes shorter than the transfer distance of when the sheet of text is bitten by both the main roller 5 and the feed roller 7, i.e., when the text is under the influence of the linear velocity of the main roller 5, therefore, one hundred percent reproduction of the transmit text is not realized.